To determine the influence of diet on serum cholesterol and triglyceride levels among adults, 24-hr dietary recall interviews were conducted among 957 men and 1,082 women resident in the community of Tecumseh, Michigan. Trained interviewers obtained detailed description of all foods consumed during 24 hr before venipuncture for lipid determination. Using a list of nutritional composition of 2,706 foods prepared from standard references, nutritionists determined quantities of all nutrients common to the American diet which were consumed by each participant according to a 24-hr diet record. For analysis, men and women were grouped into lower middle, and upper tertiles according to serum cholesterol and triglyceride levels. The mean daily consumption of each dietary component was virtually identical in all tertiles for men and women but differed between sexes. Cholesterol and triglyceride levels were unrelated to quality, quantity, or proportions of fat, carbohydrate, or protein consumed in the 24-hr recall period.